The Application Of New Technology Of MRI In The Preoperative Staging Of Rectal Cancer

Part 1 The Value of 2D MRI and 3D MRI Sequences in Preoperative Staging of Rectal Cancer Objective: To evaluate the accuracy of the preoperative local-regional staging of the rectal cancer by a two-dimensional(2D)T2-weighted TSE sequence and a three-dimensional(3D VISTA)T2-weighted turbo spin-echo(TSE)magnetic resonance(MR)sequence.Methods: 33 patients diagnosed with rectal cancer pathologically from January to April in 2016 were enrolled retrospectively.T and N staging were assessed by two radiologists independently on MR images.B oth 2D-T2 WI MRI and 3D VISTA MRI of the rectum were performed with Philips 3.0T MR on all patients.The accuracy and consistence with pathological results of TN staging using 2D and 3D sequences were calculated using SPSS 23.Results: In 33 cases,T staging accuracy values of 2D and 3D VISTA data were 70% and 85% respectively(Kappa = 0.576 and 0.790)for reviewer 1(P=0.274),and 73% and 82%(Kappa = 0.618 and 0.746)for reviewer 2(P=0.454).The agreement of VISTA T sequences 3D staging with pathologic results was excellent and better than that of 2D sequences;N category lesion staging accuracy values for 2D and 3D VISTA were 58% and 70% respectively(Kappa = 0.252 and 0.437)for reviewer 1(P=0.182),and 58% and 67%(Kappa = 0.267 and 0.376)for reviewer 2(P=0.218).The agreement of N staging 2D and VISTA 3D staging with pathological results were both poor.Conclusions: Preoperative TN staging with conventional 2D MR imaging sequence and 3D VISTA T2-weighted imaging protocols for rectal cancer patients showed no significant differences in accuracy.However,compared to 2D sequence,3D VISTA sequence has its advantages in preoperative MR staging.Part 2 Rectal Cancer: The Multi-b Value Magnetic Resonance Diffusion-Weighted Imaging —Diagnostic Accuracy and Correlation with Clinical-Pathologic Factors Objective: To evaluate the potential association between parameters derived from the multi-b value magnetic resonance diffusion-weighted imaging and clinical-pathologic factors and to investigate the ability of multi-b value of magnetic resonance diffusionweighted imaging in identification of patients with rectal cancer requiring chemo-radiation therapy.Methods: Data from 77 patients(median age,61 years;range,31-83 years)with rectal adenocarcinoma between May 2016 and December 2017 were involved in this retrospective study.Conventional diffusion-weighted imaging(DWI)(b=0,1000 sec/mm2),diffusion kurtosis imaging(DKI)(b = b=0,500,1000,1500,2000 sec/mm2)and intravoxel incoherent motion(IVIM)(b=0,20,50,100,150,200,500,800,1000 sec/mm2)were performed.Apparent diffusion coefficients(ADC)from diffusion weighted imaging,mean kurtosis(MK)and mean diffusion(MD)coefficients from DKI and slow diffusion coefficient(D),fast diffusion coefficient(D*),and perfusion-related diffusion fraction(F)form IVIM were measured by two radiologists.Student t test,Wilcoxon signed-rank test,chi-square test,Spearman correlation,and receiver operating characteristic curves(ROC)were used for statistical analysis.Results: There were a weak negative correlation between EGFR expression and MD(r =-0.249,p = 0.029),and a weak positive correlation between KI67 and EGFR expression(r = 0.354,p = 0.002);p T12/34 was weakly and positively correlated with p N0/12 and p EMVI(r = 0.311,p = 0.006;r = 0.230,p = 0.044),with a statistical difference(p = 0.006;p = 0.043);There was a moderate positive correlation between p N0/12 and p EMVI(r = 0.438,p = 0.000),with a statistical significance(p = 0.000);There was a weak positive correlation between p N0/12 and M(r = 0.293,p = 0.010),with a significant difference(p = 0.020).p EMVI was weakly and positively correlated with M and WHO grading(r = 0.395,p = 000;r = 0.249,p = 0.029).The difference was statistically significant(p = 0.004;p=0.029);The accuracy of MRI in assessing preoperative T,N staging of rectal cancer was 75% and 58%,respectively.The area under the ROC curve of MK distinguishing p T12 + 3a-b / 3c-d + 4ROC was 0.649,p = 0.025.Conclusion: Patients with rectal cancer with high EGFR expression had slightly lower MD.There was correlation between EGFR and KI67,p T12/34 and p N0/12 and p EMVI,p N0/12 and M,p EMVI and M and WHO grading.MR could accurately evaluate the preoperative staging of rectal cancer.MK could help to identify patients with rectal cancer requiring chemo-radiation therapy.